When properly designed, explosives detection sensors are really expensive. But researchers at Georgia Tech have developed a cheap, ammonia-detecting sensor that can be manufactured with an inkjet printer and some paper.

According to Gizmag, the key ingredient are silver nanopartibles, which are transformed into carbon nanotubes which attract ammonia (a component of explosives) in trace amounts.

The ink consists of silver nanoparticles held in an emulsion that can be passed through an ink-jet printer at a temperature of only 212 F (100 C). This ink is treated with ultrasonic waves in a process known as sonification, which alters the viscosity and makes the ink more homogeneous for greater effectiveness. As it sets, the ink forms into nanoscale cylinders called nanotubes.

And what makes the technology even more alluring besides being extremely cheap to produce, is that it can be calibrated to detect other types of gasses and can be built into RF or other wireless technologies (meaning it can automatically send alerts). But still being a prototype, it may still be a few years before anyone sees this invention in action. [Gizmag]